1. Technical Field
An embodiment of the invention relates to an outboard motor, particularly to an outboard motor that can detect wear debris of a gear mechanism.
2. Background Art
Conventionally, there is widely known an outboard motor in which a driving force of a prime mover such as an internal combustion engine is transmitted to a propeller through a gear mechanism. When the driving force is transmitted, gears of the gear mechanism are rubbed against each other so that they are worn, sometimes resulting in wear debris (i.e., metal powder, etc.). In the case where such wear debris is generated, it may be caught in the gear mechanism as obstacles and it possibly damages the gear mechanism, disadvantageously.
To cope with it, in Japanese Laid-Open Patent Application No. Hei 6 (1994)-33730 (730), a branch passage used to circulate oil (lubricating oil) is connected to a gear case housing the gear mechanism and the branch passage is installed with a detecting section that detects an amount of wear debris based on the degree of transparency of the oil. It makes possible to, for example, carry out the maintenance such as oil change at the time when the increase in the amount of the wear debris is detected, thereby preventing occurrence of the aforesaid defect.